Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Adverse effects
[30] Systematic review	People with herniated lumbar disc (number not reported)	Worsening of neurological symptoms with people receiving spinal manipulation with baseline Absolute results not reported
[32] Systematic review	135 cases of serious complications after spinal manipulation; published between 1950 and 1980	Serious complications with people receiving spinal manipulation with baseline Absolute results not reported
[33] Systematic review	4712 treatments in 1058 people having both cervical and lumbar spinal manipulations	Adverse effects with people receiving spinal manipulation with baseline Absolute results not reported
[34] Systematic review	People with herniated disc (number not reported)	Further disc herniation or cauda equina syndrome with people receiving spinal manipulation with baseline Absolute results not reported